WordPress right "out-of-the-box" has lots of features, is very powerful, and a great CMS (Content Management System). That why it is being used on more than 20% of new web sites today. You don't need to know html or php to develop a web site using WordPress, although I would recommend learning the basics of html and css (cascading style sheets) so that you can customize your WordPress site when you need to.
WordPress uses "sidebars" where one can add different types of content called widgets. Widgets can be a form, an image, a video, pasted in html content, a script - almost any kind of content. Sidebars can be on the left side, on the right side or both. The bottom of your site (the footer) and the top of your site (the header) can also accept widgets. The position of the sidebars, and the options you have for locating them are dependent on the "theme". If you aren't familiar with a theme, it is the structure and layout of your site, including its appearance and styling.
However, the standard WordPress package and most themes place the same widgets on every page or post of your site. From time to time, you'll want more advanced functionality so that you can show different types of widgets, and customize the widget's content to the content on your page.
There are many plug-ins that allow you to customize the content of your sidebars. Here are 2 that I like:
Custom Sidebars by WPMU DEV
Display Widgets by Strategy 11
Before installing either of these plugins, I'd recommend visiting the developers web site. Read the reviews, and select the one that best meets your needs. Should you install both plugins to try them out, then deactivate the plugin you are NOT using. Once you've made your selection, go back and remove the unused plugin from your admin area.